PARAMUS — A 20-year-old Paramus man was sentenced today in Newark federal court to five years of probation, including a year of house arrest, for possessing to more than 600 images of child pornography on a computer in his home in December 2009, federal authorities said.

He was also ordered to register as a sex offender by U.S. District Judge Dennis M. Cavanaugh, said Rebekah Carmichael, a spokeswoman for U.S. Attorney Paul S. Fishman.

Justin Birdsall pleaded guilty in March to one count of possession of child pornography, said federal authorities at the time. Authorities had also said that Birdsall resided in December 2009 with his parents and three younger siblings, ages 17, 13, and 8. Birdsall also acknowledged that the images he possessed included ones depicting minors engaging in sexually explicit conduct with both adults and other minors, authorities had said.

Today, Birdsall’s attorney, Susan C. Cassell, said in a telephone interview that her client’s relatively young age "was a huge factor" in him receiving only a probationary sentence, as opposed to prison time. In addition, she said, "he . . . has been continually in therapy for approximately a year and a half."

Cassell also pointed out that her client had not distributed or advertised child pornography images. "The extraordinary penalties in sentencing guidelines relating to child pornography, although they embrace the viewer within in their very broad statutory language, appear to be more pointedly directed in their harshness to those people who film, manufacture, advertise, distribute and sell [the child pornography images]," she said.